1. Field of the Invention
The present invention relates to a cleaning apparatus which cleans a platen roller of a printing apparatus and a printing apparatus using the cleaning apparatus, for example.
2. Description of the Related Art
As a printing apparatus, an apparatus of a thermal transfer type where ink of a thermal transfer ink ribbon is thermally transferred to an image receiving layer of an intermediate transfer film to form an image, and pressure and heat are applied to the image so that an image for personal authentication such as, especially, a license or a passport, or a character image such as personal information is recorded on a medium to be recorded has been known.
Such a printing apparatus is provided with a thermal head and a platen roller made of, for example, urethane rubber and spaced from the thermal head in a facing manner thereto. A melting ink ribbon and an intermediate transfer film disposed in a superimposed state are interposed between the thermal head and the platen roller.
The thermal head comes into pressure contact with the platen roller via the melting ink ribbon and the intermediate transfer film to heat the melting ink ribbon and the intermediate transfer film, thereby printing an image on an image reception and adhesion layer surface of the intermediate transfer film.
A cleaning roller for cleaning a surface of the platen roller is provided near the platen roller. The cleaning roller comes in contact with a surface of the platen roller to rotate according to rotation of the platen roller, thereby removing dirt on the platen roller (see Jpn. Pat. Applin. KOKAI Publication No. 2005-225168, for example).
Now, such a phenomenon that the platen roller swells according to degree of use of the platen roller so that its diameter becomes uneven along an axial direction of the platen roller takes place. When this phenomenon takes place, contact pressure between the platen roller and the intermediate transfer film becomes uneven along the axial direction, so that such a problem that difference between dark and light in the axial direction occurs on a printed image. It is thought that the swelling of the platen roller is caused by a relationship between the cleaning roller and the platen roller at a step of bringing the cleaning roller into contact with the platen roller and rotating the cleaning roller according to rotation of the platen roller at a fixed time interval for cleaning dirt of the platen roller.
In the conventional art, however, a platen roller made of urethane rubber and a cleaning roller made of rubber are used, but swelling of the platen roller cannot be prevented sufficiently. Therefore, contact pressure between the platen roller and the intermediate transfer film becomes uneven in the axial direction, which results in such a problem that a dark and light pattern along the axial direction occurs on a printed image.